Investigation on Vinegar.

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Introduction

Chemistry Coursework: Investigation on Vinegar Getting the Results I am going to measure the amount of acid in certain types of vinegar. I will use the following vinegars: white wine, cider, red wine, malt and distilled malt. I will use a NaOH 01m or 0.4m to see when the vinegar turns the alkali neutral. To show when the vinegar turns neutral I will either will use phenolphthalein or methyl orange indicator. The methyl orange turns a peach colour and the phenolphthalein goes completely clear from being a pinky colour! Apparatus * 1x Burette * 1x Pipette * 1x Pipette filler * 3 x Beaker * 1x Funnel * 1x Different vinegars * 1x Alkali * 1x Clamp stand * 1x White mat * 1x Burette clip Method 1. Collect all of the apparatus. 2. Set up the equipment like above. 3. Fill the Burette with the type of vinegar. 4. Put 10cm cubed of the alkali into a beaker and add 2-4 drops of indicator to the alkali. 5. Take a rough measurement by opening the tap of the burette and stopping every 1 cm cubed. 6. When the indicator changes take the measurement. 7. Wash out all equipment with distilled water. 8. Start again stopping at 4 cm cubed below the first measurement adding the vinegar slowly and mixing it up. To find out the concentration of etanoic acid in each vinegar you have to use bMaVa = aMbVb. ...read more.

Middle

There are two different ways of making vinegar either a slow way or a quicker way. The slow way is to use a weak alcohol from about 5 to 10%. You then leave the alcohol outside for about 4 weeks. The hotter the temperature the quicker the change. You then leave it to settle in a cool place until clear. The reason it turns into vinegar is because the ethanoic acid gets oxidised then turns into acetic acid. The more ethanoic acid the more acetic acid thus meaning it is stronger. Hypothesis' As it says above the making of vinegar is made by the oxidation of alcohol. As this is true I think that red wine would be the strongest of the vinegar's, then white wine, then cider, then distilled and finally malt vinegar. Red wine as it is the most alcoholic will be the strongest vinegar. Also distilled will be the stronger than malt as it has no impurities. Preliminary Results For my preliminary results I had to choose what strength of alkali I should use and also which indicator I should use. I tested all the vinegars with both strengths of alkali and with both indicators. The first thing that I noticed was that I t was impossible to use 0.4 moles of NaOH as it was too strong to be distilled by the vinegar's. This meant I would have to use 0.1 moles of NaOH as it stays on the scale and comes up with a good reading. ...read more.

Conclusion

Cider Vinegar: 1 x Ma x 10.20 = 1 x 0.1 x 10 Ma = 0.098 x 10 = 0.98 You have to multiply by 10 as it is diluted! Red Wine Vinegar: 1 x Ma x 8.1 = 1 x 0.1 x 10 Ma = 0.123 x 10 = 1.23 You have to multiply by 10 as it is diluted! Malt Vinegar: 1 x Ma x 11.5 = 1 x 0.1 x 10 Ma = 0.087 x 10 = 0.87 You have to multiply by 10 as it is diluted! Diss. Malt Vinegar: 1 x Ma x 11.37 = 1 x 0.1 x 10 Ma = 0.088 x 10 = 0.88 You have to multiply by 10 as it is diluted! This means that they go in the following order: * Red wine Strongest * White wine * Cider * Diss. Malt * Malt This proves that my hypothesis was true and that the equation was right. The experiment has worked very well and has been a success. I had 2 anomalies but I repeated these so they were fine. I then used these to work out the average. It shows that the more alcohol in a vinegar the stronger the vinegar is. If I did it again I would try and use a better way of measuring when it is neutralised! 1 Oli Jones 4 Aleph ...read more.

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